public static void AddFlashMessage(this TempDataDictionary dictionary, UserMessage flashMessage)
{
var messages = (ICollection<UserMessage>)dictionary[FlashMessageKey];
if (messages == null)
{
messages = new List<UserMessage>();
dictionary[FlashMessageKey] = messages;
}
messages.Add(flashMessage);
}
protected void AddUserMessage(UserMessage message)
{
TempData.AddFlashMessage(message);
}